1. Field of the Invention
This invention relates generally to flexible bag sealing apparatus and methods for vacuum sealing flexible plastic bags, and more particularly to a sealing system and method for vacuum sealing conventional plastic bags of the type having a mating male rib or bead and female sealing channel along the length of the bag opening.
2. Background Art
Closable plastic bags, particularly food storage bags, such as those commercially known as ZIPLOC® or GLAD-LOCK® bags, are widely used to preserve food. Such bags, also known as “zipper bags” or “profile bags”, typically have a mating male rib or bead and female channel extending along the opening of the bag that form an airtight closure when properly aligned and pressed together along the length of the bag opening. Naito, U.S. Pat. RE 28,969 discloses an example of an airtight profile closure is that used in the ZIPLOC® storage bag. The airtight closure it typically formed as an integral part of the bag and allows products stored in the bag to be easily removed and re-stored.
The freshness and quality of the product stored within the bag is to a large measure dependent upon the bag being substantially free of air. Thus, to preserve the contents of the bag in a fresh state, without loss of flavor and texture, it is desirable to evacuate or vacuum seal the bag. In sealing such profile closure bags, the user will usually attempt to manually squeeze the air from the bag while simultaneously trying to seal the opening. Unfortunately, the volume of air removed is generally inadequate, and air can still re-enter and become trapped in the bag upon initial sealing or re-sealing.
Others have attempted to overcome problems associated with manually sealing such profile closures by modifying the closure, providing specially designed bags, or providing bag attachments for evacuating the bag.
Kugler, U.S. Pat. No. 3,339,606 discloses a tongue and grove profile closure wherein the tongue is of a thickness less than the width of the groove and a releasable pressure sensitive adhesive is provided to keep the tongue within the groove. Adhesives, however, are difficult to apply, and may cause undesirable problems by sticking to other bags or miscellaneous surfaces.
Goto et al, U.S. Pat. No. 5,701,996 discloses a specially designed snap-fastener bag having a deaerating passage along a bottom-seal and a conventional snap fastener provided along the bag opening. The deaerating passage has an opening through one side of the bag and a sticky substance, such as polybutene, is disposed in the passageway to adhere the top and bottom plies of the plastic film of the bag after manually deaerating the bag.
Cox, U.S. Pat. No. 5,544,752, and Lambert, U.S. Pat. No. 6,085,906 disclose specially constructed evacuable storage bags having an integrally formed flexible conduit directed through the bag and into fluid communication with the interior of the bag and sealing strips positioned within or on the exterior of the conduit wherein pressure applied to an exterior of the conduit will effect collapsing thereof and cooperative engagement of the conduit sealing strips to preclude fluid communication through the conduit.
Kaufman, U.S. Pat. No. 4,018,253 discloses a vacuum device for freezer bags which includes a hollow retainer member adapted to receive the open end of the bag, and a cap member which is adapted to fit over the outside surface of the retainer in airtight engagement therewith. A flexible tube extends downwardly through the bottom end of the cap member and upwardly above the cap member, and a valve is provided on the upward part of the tube. The open end of the bag is inserted through the hollow retainer and draped over the top end of the retainer, and the cap is mounted over the top surface of the retainer and the open end of the bag in airtight engagement therewith so that the tube passage is in airtight communication with the interior of the bag. Air is withdrawn from the container through the tube, and the valve on the tube is then closed to close the tube passage.
Others have attempted to overcome problems associated with manually sealing bags having conventional profile closures by providing nozzle attachments that are to be connected with a household vacuum cleaner hose for evacuating the bag, which require additional time and trouble to relocate the vacuum cleaner.
Brown, U.S. Pat. No. 6,763,857 discloses a vacuum attachment for use with a vacuum hose and a vacuum device, and a conventional plastic food storage bag. The vacuum attachment has a first hollow substantially frustoconical attachment member for attaching the vacuum attachment to the vacuum hose, and a generally cylindrical inserter member for inserting the vacuum attachment into the bag. The vacuum attachment may also have an air flow blocker for blocking the air flow between the bag and the vacuum attachment. The air flow blocker is a hollow substantially cylindrical cap with a closed end, and may be provided with an opening or a filter.
Smith, U.S. Pat. No. 5,873,217 discloses a vacuum sealing method and nozzle adaptor apparatus for sealing a container such as a zipper-type plastic bag. The nozzle adapter has an elongated nozzle end for insertion into the container or bag and a larger vacuum hose-engaging end for engaging the hose of an existing vacuum source such as household vacuum cleaner. The elongate end of the nozzle is placed in the bag, the bag is sealed as completely as possible around the nozzle, the vacuum source is turned on. After the air is withdrawn from the bag, the nozzle is quickly removed from the bag and the open portion of the zipper-type seal is quickly engaged before a substantial amount of air can return into the bag.
Lau, U.S. Pat. No. 5,287,680 overcomes the problems associated with vacuum cleaner nozzle attachments by providing a hand-held battery operated vacuum packing device for evacuating and sealing a conventional plastic bag. The device has a housing with a pair of jaw elements mounted on a lever with a slot therebetween through which the edges of the bag are pulled to press fit the edges together. A nozzle extends outwardly from the housing and an air extractor fan in the housing withdraws air from the bag immediately before sealing is complete. With the jaws in an open position, the two mating edges of the bag are threaded together into the slot between the two jaw elements and the nozzle is placed in the bag. The lever is then operated to close the jaws. The bag and the vacuum packing device are then pulled in opposite directions, so that the two edges of the bag are pulled past the nozzle and through the slot into sealing engagement with one another. When the bag is sealed along almost the entire length of the edges, the extractor fan is operated to extract air from the bag through the nozzle. The lever is then released to open the jaws and the nozzle is withdrawn, and the sealing of the bag is completed manually.
A variety of specially designed large storage bags having air valve arrangements are also known in the art, such as disclosed in Yeager, U.S. Pat. No. 5,829,884 and Koyanagi, U.S. Pat. No. 6,499,600 have been proposed for the purpose of removing air from the storage bags in order to reduce the volume of an item, such as clothing, inside the bag to facilitate storage.
A variety of combination vacuum and heat sealing devices that include an electrical heat sealing unit combined with a vacuum pump are known in the art. Most of these types of heat sealing devices are not particularly suited for use with conventional profile closure bags and require special plastic bags, and some may cause burns and/or fumes, which may be potentially harmful.
Consequently, a need exists for a vacuum sealing system that will allow the user to vacuum pack the contents of a resealable flexible plastic bag that overcomes the foregoing drawbacks.
The present invention is distinguished over the prior art in general, and these patents in particular by a vacuum sealing method and system for evacuating air from and sealing a flexible plastic bag of the type having a mating male rib and a female sealing channel closure along the length of the bag opening, wherein a flowable liquid is applied to the female channel, the rib and channel are engaged along their length to leave a short portion of the closure unclosed, a hollow tubular evacuation tube connected with a vacuum pump is inserted into the bag through the unclosed portion, pinching pressure is manually applied to sandwich the evacuation tube between the unclosed portion to prevent air from escaping, the vacuum pump is operated to withdraw a substantial amount of air from the bag, and thereafter the evacuation tube is quickly pulled from the bag so that the pinching pressure is transferred to the closure thereby closing the unclosed portion and sealing the evacuated bag with the liquid filling voids between the mating elements and providing a supplemental seal to increase resistance to air entering the sealed bag.